Gas turbine engines (“GTE”) are known to include several different sections that work together to generate power. For example, a GTE is known to include a compressor, a combustor, and a turbine. The compressor receives ambient air, compresses the air, and then forwards at least a portion of the compressed air into a combustion chamber of the combustor. While in the combustion chamber, the compressed air combines with fuel, and the GTE ignites the air/fuel mixture to create a flow of high-temperature compressed gas that flows into the turbine. The flow of high-temperature compressed gas impacts turbine blades, which cause one or more turbine rotors to rotate. Rotational energy from each turbine rotor is transferred to a drive axle to power a load, for example, a generator, a compressor, or a pump. Some of the compressed air from the compressor may be diverted before the combustion process for use as a flow of cooling air.
It is also known to include an inspection hole in a GTE, for example, passing through an outer casing of the GTE to permit access to an interior portion of the GTE. The inspection hole allows for inspection of the interior portions of the GTE by inspection tools or instruments, such as a borescope. Interior inspection of the GTE by the instrument through the inspection hole is typically performed during periods of maintenance, for example, when the GTE is not operating. Before the GTE returns to operation, the inspection hole is sealed, for example, by an inspection hole plug. Some GTEs are known to include a wall separating different flows of gas through the GTE. For, example, a flow of cooling gas may be separated from a flow of high-temperature gas by an internal wall. Temperature variations within the GTE may cause thermal expansion of components within the inspection hole (e.g., an inspection hole plug), and the amount of thermal expansion of each component may vary based on its proximity to the flow of high-temperature gas. Thermal expansion is known to cause undesired stresses in an inspection hole plug, which commonly leads to premature fatigue and failure of the plug.
One example of a system including an inspection hole plug is described in U.S. Pat. No. 5,431,534 to Charbonnel (“the '534 patent”). The '534 patent discloses a plug for sealing an inspection hole in each of a plurality of walls. The plug includes a pair of sealing units, wherein each of the sealing units is rotatably attached to a link rod. The plug includes a housing to cover the inspection hole. Further, the plug includes a spring to bias the sealing units away from the housing. The '534 patent states that the rotatably attached sealing units allow for thermal expansion.
Although the system of the '534 patent may disclose an inspection hole plug including a pair of sealing units that accommodate some thermal expansion, certain disadvantages persist. For example, a plug with two points of rotation may prove difficult during assembly when the inspection hole is not directly aligned with the directional force of gravity. That is, the sealing units may rotate out of alignment with the rest of the plug due to gravity and, therefore, may prove difficult to align within the inspection holes of the machine. In addition to problems with assembly, the use of a two rotating elements and a spring bias assembly may unnecessarily increase the complexity and cost of the inspection hole plug.